MIPS: kconfig: add options for dbau1x00 board variant select

The dbau1x00 board can be built with various variants which are
configured via CONFIG_SYS_EXTRA_OPTIONS. This is deprecated. Thus
add new Kconfig options for those board variants.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

board/dbau1x00/Kconfig

@@ -9,4 +9,22 @@ config SYS_SOC
 config SYS_CONFIG_NAME
 	default "dbau1x00"
 
+menu "dbau1x00 board options"
+
+choice
+	prompt "Select au1x00 SoC type"
+
+config DBAU1100
+	bool "Select AU1100"
+
+config DBAU1500
+	bool "Select AU1500"
+
+config DBAU1550
+	bool "Select AU1550"
+
+endchoice
+
+endmenu
+
 endif

configs/dbau1100_defconfig

@@ -1,4 +1,4 @@
-CONFIG_SYS_EXTRA_OPTIONS="DBAU1100"
 CONFIG_MIPS=y
 CONFIG_TARGET_DBAU1X00=y
 CONFIG_SYS_BIG_ENDIAN=y
+CONFIG_DBAU1100=y

configs/dbau1500_defconfig

@@ -1,4 +1,4 @@
-CONFIG_SYS_EXTRA_OPTIONS="DBAU1500"
 CONFIG_MIPS=y
 CONFIG_TARGET_DBAU1X00=y
 CONFIG_SYS_BIG_ENDIAN=y
+CONFIG_DBAU1500=y

configs/dbau1550_defconfig

@@ -1,4 +1,4 @@
-CONFIG_SYS_EXTRA_OPTIONS="DBAU1550"
 CONFIG_MIPS=y
 CONFIG_TARGET_DBAU1X00=y
 CONFIG_SYS_BIG_ENDIAN=y
+CONFIG_DBAU1550=y

configs/dbau1550_el_defconfig

@@ -1,4 +1,4 @@
-CONFIG_SYS_EXTRA_OPTIONS="DBAU1550"
 CONFIG_MIPS=y
 CONFIG_TARGET_DBAU1X00=y
 CONFIG_SYS_LITTLE_ENDIAN=y
+CONFIG_DBAU1550=y